Conventionally, a sensor mounted onto a substrate, such as a proximity sensor, has been known (for example, refer to PTL 1).
According to PTL 1, a light receiver and a light emitter are arranged side by side in a circuit substrate, and a first translucent member and a second translucent member are covered with a light shielding member while the light receiver is covered with the first translucent member and the light emitter is covered with the second translucent member, so that a proximity sensor is mounted onto the substrate.